Field
The present invention generally relates to heat-transfer systems and, in particular, to a bendable heat pipe having an axial wick insert.
Description of the Related Art
In conventional heat pipes, a liquid-phase working fluid is provided to an evaporator whereupon the working fluid extracts heat from the evaporator and is converted to a vapor-phase by evaporation. The vapor-phase working fluid is conveyed to a condenser wherein the working fluid rejects heat to a heat sink by condensation and is thereby returned to the liquid-phase.
Some conventional heat pipes, particularly heat pipes intended for use in low-gravity environments utilize arteries, i.e. channels, to provide capillary pressure to circulate the liquid-phase working fluid from the condenser to the evaporator. Some low-gravity heat pipes provide arterial wicks wherein the arteries carrying the liquid-phase working fluid are separated from the gas-phase region by a capillary-scale slot or a fine-weave mesh. Conventional arterial heat pipes, however, are susceptible to bubble-induced failures and, in addition, may fail to prime properly in a low-gravity environment. Bubbles may form in the liquid working fluid, such bubbles being particularly persistent in the presence of non-condensable gases, i.e. gases other than the heat pipe working fluid, that may be present as impurities or may evolve by chemical reaction during operation of the heat pipe.
Certain conventional arterial heat pipes may provide one or more wicks as an insert within the gas-phase region of the heat pipe. Wick inserts having machined structures may have limited flexibility, thereby presenting a challenge for use in deployable heat management systems, and inserted wick inserts having porous structures may have substantially lower heat transport capabilities, thereby presenting a challenge for use in a high-performance system such as may be required on space vehicles.